The present invention relates to a system for communicating data between an implantable medical device (IMD) and an external processing unit.
Since the introduction of the first implantable pacemakers in the 1960s, there have been considerable advancements in both the field of electronics and medicine, such that there is presently a wide assortment of commercially available body-implantable electronic medical devices. The class of IMDs now includes pacemakers, implantable cardioverters, defibrillators, neural stimulators, and drug administering devices, among others. Today's state-of-the-art IMDs are vastly more sophisticated and complex than early ones, and are capable of performing significantly more complex tasks. The therapeutic benefits of such devices have been well proven.
It has proven useful for IMDs to have the capability of communicating data with an external processing unit that in turn has the ability to process, store and/or display data provided by the device. The data provided by the device may be real-time or recorded data. The external unit may also transmit signals to the implanted medical device in order to provide some control over the device. This communication is achieved by wireless telemetry, the physical characteristics of which are known in the art.
Existing implantable medical device systems have relied on the external processing unit to initiate data communication with the IMD, at least in part due to processing limitations of the IMD. A typical scenario in such a system is as follows:
(1) “Wake up” implantable device, such as with wireless transmission, a magnet, or other initiating means.
(2) Implantable device transmits device identification information.
(3) External processing unit identifies device and loads appropriate application program.
(4) External processing unit interrogates implantable device to determine configuration of device, such as type or format of data that will be transmitted, etc.
(5) Implantable device transmits data to external processing unit according to format and configuration established.
(6) External processing unit initiates change in data type or format to be transmitted by implantable device by transmitting command to device.
(7) Implantable device adjusts the type or format of the data transmission.
This communication scenario illustrates the necessity, in existing systems, of a specific application program for each type of device and for each data characteristic (data type, structure or format) supported by the device, so that proper manipulation of the raw data transmitted by the implantable device can be done according to the configuration determined by the external processing unit by interrogation. While these systems have provided excellent results in situations where application programs and IMDs are specifically designed to work together, it would be useful to provide a system in which at least some level of data communication and cooperation is available even when the application program is not specifically designed for a particular IMD or data characteristic.